The explosive device was placed inside a newspaper box outside Mamie’s Kitchen on Pleasant Street. It exploded around 4 a.m. Sunday, sending debris through a restaurant window and damaging a door and wall.

“Probably just a bunch of kids with fireworks. No, I’m not worried at all,” said Alicia DeWolfe, the owner of Mamie’s Kitchen.

Police, though, are taking the matter seriously, according to Detective Steve Mizzoni.

“The explosives used are very powerful. It was not your standard fireworks or M80. It was something much more substantial. It could have killed somebody,” said Det. Mizzoni.

The $5,000 reward is being offered for information leading to the arrest of the person or people responsible.

“Whoever placed this device could make another, and could place it in a spot where it could be occupied by large crowds,” said Det. Mizzoni.